Description: The Microscopy Facility, in existence at The Wistar Institute since 1973, provides a wide range of services for morphological analysis of biological structure at the light and electron microscopic level of resolution. The capabilities of the facility include the imaging of structure using light microscopy, fluorescence confocal microscopy, transmission electron microscopy assays, and scanning microscopy (performed at a remote location). The recent addition of the Leica confocal microscope in 1994 expanded the quality of service by providing state-of-the-art single cell assays and thick specimen analyses as well as high resolution in situ hybridization techniques. The facilities are located in the basement of the 1894 Building, occupying an area selected for the lowest magnetic fields and minimum vibration. Since the facility renovation in 1989, a total of 564 square feet is dedicated to the collective support of microscopy-related activities, including an office for the Director, Dr. Maul. During the current funding period, the facility housed two major pieces of equipment: A Leica confocal scanning microscope and a Leitz EM10 electron microscope equipped for stereo microscopy. The facility has contributed to the research of 30 Wistar investigators from Center-supported laboratories. The usage for current peer-reviewed projects was 29 percent, and for non-peer reviewed projects was 27 percent.